Some things that come to mind if you want to make a street Jeep, would be low profile tires such as Pirelli or Continentals on 18-20"rims. Suspension companies I remember from my Maxima days were brands like KYB, Koni, Eibach, Energy Suspension, Addco.
The steel hood weighs about 2 tons, if a fiberglass one would reduce the weight if someone would make it but any weight reduction would be plus.
As far as engine mods, some people claim to have luck with Chips, and Air intakes. Keneth Bell made a supercharger for it, but when people installed in the 3.7 it blew it to pieces. Things like a forged Crank, Pistons and Piston rods would fix that.
The trans is another issue, a 5 or more speed would be much better, however, they way the geniuses at Chrysler engineered so you are stuck using the 42rle 4spd slush box.
Good luck in your build. Another thing you could do is trade it for a Nitro with the 4.0 and 5 spd.
When you get knee-deep in a situation, floor it.